Tag: arraylist

Add contents of Array List to a JSON Array: Java

I have an Array List called getFields: This array list logs out the following: I need to convert getFields into a JSON Array called jsArray, so I have done this: jsArray logs out the following: The problem is, I do not want jsArray to have a nested array (i.e. I don’t want it to have double square brackets). I want

In java, what’s the correct syntax for creating/constructing/defining a named variable on the same line as I add it to an arraylist?

arraylist java syntax

I’m populating an arraylist in Java, and I’m wondering if it’s possible to cuts some lines by doing the following (except complete): myArraylist.add(new objectname varname (constructor things)); instead of: objectname varname = new objectname(constructor things); myArrayList.add(varname); Answer You can do the following (using a record as an example). But you won’t have any other named instances of the created classes.

Tic Tac Toe runs and functions completely, but after getting 3 in a row, another move has to be made for it to end [closed]

arraylist if-statement java while-loop

Closed. This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 1 year ago. Improve this question Is anyone of you able to find out why it loops around 1 extra time even though the while condition

Why does this ArrayList ‘add’ operation not add the new element? [closed]

arraylist java

Closed. This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed last year. Improve this question When I run this code I expect an ArrayList with one element, the String “Hi”, to be added to the ArrayList at the 0th index. When

How to use Collections.binarySearch for ArrayList<List> arr in java

arraylist binary-search java string

I have an ArrayList<List<String>> and im trying to use the built-in binary search in the collection but I always come up with an error int index = Collections.binarySearch(arraylistdata, id); Where arraylistdata is my ArrayList of List<String>. Answer This works fine, but you need to known that Collections#binarySearch accept a List<? extends Comparable<? super T>> as its first parameter. While in

Merge two object lists in java of the same type [closed]

arraylist data-structures java merge tobjectlist

Closed. This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 1 year ago. Improve this question How do i merge two object lists in java for eg: i have 2 lists listA listB with one object each like listA[name=abc,age=56, weight=null] listB[name=Null,age=Null,weight=70]

How to have one array to Store a String and another to cout how many times that String was used?

arraylist counter java

I’m making an app for an ice cream shop where I need at some point to know how many ice cream from a specific flavor were sold. I have to write the flavor of the ice cream when I add it to the stock, so the ArrayList that contains the flavor is initially empty. Then I need another ArrayList which

Why clear() on one ArrayList is clearing elements in another ArrayList?

arraylist collections java

My desired output should be: [[1], [1, 2], [1, 2, 3], [1, 2, 3, 4], [1, 2, 3, 4, 5]] By creating new ArrayList object every time I am getting the desired output as [[1], [1, 2], [1, 2, 3], [1, 2, 3, 4], [1, 2, 3, 4, 5]] But, not getting same result when trying to use clear() (to